Watering – Addressing the Most Common Mistake in Lawn Care

Whether you have an irrigation system or you water by hand, understanding the basics of watering your grass will help you maintain a beautiful lawn throughout the year. Often times incorrect watering can lead to more problems than not watering at all. How many times have you seen somebody watering in the mid-day sun, watering half the street, or when it’s raining? This article will cover 4 of the most common questions regarding watering, and also include some general tips.

1. How to Tell if Your Lawn Needs Water?

Your lawn will tell you when it needs watering, provided you know the signs. Don’t just turn on your sprinkler system because it’s been a few days since the last watering. Instead, wait to see signs of drought stress in the grass. When your grass begins to take on a blue-grey tint, curl up or wilt at the ends, and footprints on the grass stick around for longer than usual, these are signs that it is time to water.

In fact, allowing grass to experience a small degree of drought stress before watering actually encourages roots to grow farther down in search of moisture, which in turn makes your lawn more stable overall. Once you begin to see signs of stress, water the lawn again.

2. How Often to Water Your Lawn?

The experts all agree that it’s better to water your lawn infrequently. During the hottest part of the year, water 2 to 3 times a week (adjusting for rainfall), rather than a little bit every day. Watering less frequently also allows the root zone to dry in between watering. More water is required during the summer months and during hot weather. Conversely, less water is required during the spring and fall and during cool weather.

During certain times in the summer when high temperatures are the norm, depending on the size of your lawn and possible water restrictions, you should consider allowing your lawn to go into dormancy. Dormancy is the process of naturally slowing down, and eventually stopping the lawn’s growth during extreme conditions – and occurs when your lawn doesn’t receive any water. It will eventually take on a yellowish color. In this state it’s not dead, as many people think, it’s simply dormant.

Grass is extremely resilient and naturally responds to droughts by developing a deep root system, maximizing its ability to absorb soil moisture. If dry conditions persist, a deeply rooted lawn merely goes dormant until the next rain. Letting your grass go dormant should be a conscious decision as you want to avoid confusing your lawn– ie. putting it in and out of dormancy sporadically. This weakens it and opens it up to disease etc.

In my case, given the size of my yard (not huge), and manageable temperatures, so far I’ve opted not to let mine go dormant. It can often be a prudent decision however.

3. When’s The Best Time to Water your Lawn?

If possible, water early in the day when lawns are normally wet from dew, the air is still cool, the wind is calm, allowing more water to reach the root zone. Anywhere between 4am and 9am is ideal.

Can you water your lawn during the day?

Do not water during midday or when the temperature is at its peak, since it is more likely to evaporate before absorbing in the roots.

Watering your Lawn at Night

Avoid watering at night due to potential increased chances of some diseases gaining a foothold. The exception to this is when you are in extremely hot weather and nighttime temperatures don’t go below 68 degrees. Then it is better to water in the late afternoon or early evening.

Can I Water my Lawn After Mowing?

After mowing the lawn, people often are compelled to turn on the sprinklers and water the grass. If your lawn needs water this is fine, but there’s no particular need to do it immediately after mowing. You should schedule your mowing and watering for when your lawn needs them.

It is safe however to do so, although the same guidelines apply regarding the best time of day to water.  Watering late in the afternoon or at night can encourage disease, because the grass doesn’t have time to dry.

Can I Water my Lawn After Fertilizing?

Don’t water heavily right after fertilizing. This is to reduce the possibility of having fertilizer wash into the water system. Excess watering may lead to fertilizer wash. Therefore, it is recommended to hold off on watering after fertilizing your lawn for a couple of days. Furthermore, using minimal watering will actually assist fertilizers in easily absorbing into the soil.

4. How Much Water Should I be Applying?

As a rule of thumb, turf grass needs about an inch of water per week in the summer to maintain green color and active growth, less when the weather is cool, and sometimes a little more in particularly hot, dry weather. A third of an inch three times a week, or half an inch twice a week. You should ensure that you are applying enough water to deeply penetrate and moisten the root zone, anywhere between four to twelve inches into the soil. It’s important to water to at least a minimum soil depth of 4 inches, if not you should adjust your watering schedule accordingly.

The best way to determine how deep the water has soaked in and the depth of the root zone, is to dig a small hole into the watered area . An inch of water a week is usually enough to moisten the soil to 4″ – 6″ below the surface for clay soils and 8 – 10″ for sandy soils. You might also try the screwdriver test: Pushing a screwdriver into the ground will be difficult if the soil is very dry.

The reason this is so important is that over watering your lawn actually causes more damage than a lack of water. Most turf grasses can handle dry spells, but not flooding. If you over water, roots stay within the top few inches of the soil’s surface, making the grass dependent on you for its survival and it becomes more susceptible to fungus and diseases.

Every so often, take the time to dig into your lawn to verify how deeply water is actually penetrating, as it can vary with changing levels of compaction. This can be done fairly easily with a spade shovel without making a big mess of your lawn. It also lets you check the overall composition of the grass – root depth and amount of thatch. If your roots are only reaching 2-3 inches or less, your soil is likely too compacted and could benefit from core aeration. Strong roots should go down at least 4 inches into the soil.

Soil Types

Figure out the soil type in your yard to make the most effective lawn watering decisions. For example, if you see sitting water each time you water, your soil likely has high clay content. These types of soils can’t absorb water quickly (sometimes only 1/4” per hour), so instead they require repeated, shorter watering cycles (see irrigation tips). Anything over that just runs off, wasting water and your money. On the positive side, clay soil retains water longer than sandy soil, which needs more frequent watering because it dries out more quickly. Consider taking a soil test to learn about your soil, and adjust irrigation cycles accordingly. Only water as much as your lawn can efficiently absorb.

One way to improve how much water your lawn can adsorb is through annual core aeration (see my article on Fall lawn Tips). Core aeration essentially removes plugs of grass from your lawn, which reduces compaction and gives water a place to go.

5. GENERAL TIPS

Monitoring Rainfall

In order to know how much water your lawn is getting, you need to accurately measure rainfall, guessing tends to not be very effective. For measuring rain I highly recommend picking up a rain gauge. If at the end of the week it’s rained enough, hold off watering. Even if your irrigation system has a rain gauge I recommend tracking your rainfall manually as a means of comparison. In my experience, irrigation system rain gauges are not that accurate. I use the Stratus Precision. It’s the best one on the market. Check price on Amazon. If you’d rather not go outside to check your rain fall, there are automated options as well.

During expected or actual rainfall you should cease all watering. Gauge the intensity of rainfall and track it on a weekly basis, making adjustments to your watering schedule as necessary. There are no short cuts in this department. Once your sprinklers or irrigation system is setup and tested, monitoring rainfall and adjusting your schedule is really all you need to do.

Measuring Sprinkler Output – How Long do you Leave the Sprinkler On?

In order for the math to add up, you also need to know how much water your sprinklers are applying. Your lawn watering time is dictated by how much water your sprinklers are delivering. To test your sprinkler setup, place a number of small containers, such as tuna cans, around your property in the path of your sprinklers. After a session of watering, compare levels in the containers. Make adjustments to your schedule as necessary based on that knowledge. If it’s a quarter-inch deep, for example, you’ll know the lawn needs an hour-long session each week, not including rainfall.

This test can also reveal deficiencies in an irrigation system’s coverage, such as uneven coverage. Adjust accordingly to avoid over watering an entire lawn just to green up a few missed spots. This test should be performed periodically to confirm output.

If you’re not excited about the prospect of using tuna cans, you can also use these mini rain gauges that come in a 10 pack, which I bought (from Amazon). I highly recommend them. They’re cheap and very easy to read.

Best Practices with a Sprinkler System

  • People with sprinkler systems almost always use more water because watering is so easy, so they need to watch carefully that they are following best practices.
  • Water Evenly. Make sure you’re getting coverage over your entire lawn. To avoid dry spots, sprinkler heads should be positioned so they overlap slightly in their coverage areas, without spraying roads or buildings.
  • Every so often, observe your sprinklers in action, looking for clogged or leaking heads. Repair or replace valves if they are leaking. If you see a fine mist or fog during watering, your water pressure may be too high.
  • Try cutting in half the amount of time you water each zone, but run your watering program twice. In other words, instead of watering each zone for 30 minutes, water each zone for 15 minutes, then cycle through all the zones a second time. That will give the ground time to absorb the initial watering before it receives more. Spacing the cycles an hour apart will make this even more effective.

Best Practices with a Hose-End Sprinkler

  • If you use a hose end sprinkler to water your lawn, make sure you’re aware of the different types of sprinklers in order to find the one that suits your lawn shape best.
  • Traditional oscillating sprinklers are great for large, square lawns. I like this one from Gardena. For really small lawns, consider a sprinkler that sprays a small, specific pattern.
  • I’m personally a big fan of impulse sprinklers. They are highly adjustable (from 20°-360°) with infinite pattern adjustment; they can spray over a 40′ radius, and they make very efficient use of water, even in high winds, as the water stays low to the ground. Also, they rarely, if ever, get clogged because the water discharge hole is very large. I use these from Rain Bird. (see my article on DIY irrigation).

  • Similar to irrigation systems, make sure you water evenly and that you’re getting coverage over your entire lawn.
  • Lastly, install a quick-connect coupling to the end of your garden hose so you can quickly attach and detach the hose from the sprinkler. I got my quick connect couplings from RONA because they were cheap, but I plan on replacing them as they tend to leak. Looking at reviews I plan on trying these from Melnor. I like them more than the brass ones, because they have the water shutoff feature.  Let me know in the comments if you have any recommendations.

Get a Timer

If you’re watching the clock and trying to remember to shut off the water on time, chances are that sometimes you’ll sit down to watch TV or take a shower and forget that the sprinklers are running. So get a timer. They start at about $10 and turn off the water automatically after a designated time to ensure the lawn gets the proper amount of water. The timer connects to your outdoor faucet, then the hose connects to the timer. With a timer, you don’t have to worry if you forget that the sprinklers are on.

Use timers that are battery-powered to automatically turn your sprinkler(s) on and off. Choose a timer that permits you to set the sprinkler’s time and day of the week. Also important is a timer that can be set to run multiple times in a day, which is especially important for new grass. I’ve found that a lot of timers don’t have this feature. Have a look at my article on Irrigation for my recommendation.

If you want to get more sophisticated, consider a smart or automatic timer in your lawn irrigation set-up. Smart timers gauge irrigation schedules based on local rainfall, average temperatures etc. Based on my research to date, however, I would recommend a programmable timer over a smart/automatic timer. I just don’t think they’re good enough yet.

I’ve noticed a similar phenomenon with smart thermostats, like Nest. I have one and love it, however I don’t think they’re really smart enough yet to setup a heating and cooling schedule on their own. They just never seem to get it quite right. Hopefully someday both thermostats and irrigation timers will be smarter than me : ) Please let me know in the comments if you disagree or have a recommendation for me to try.

Some further considerations to make regarding timers are:

  • Set your timer to water during low water-use hours, if those are in effect in your area. They usually coincide with an early morning irrigation schedule, which is also good for minimizing water loss.
  • Reset your irrigation timer frequently. This is one of the most overlooked parts of a lawn irrigation.

Watering Hills and Slopes

When watering slopes or hillsides, play with the your frequency and timings. You’ll have the most luck if you use shorter watering cycles with time in between. Water the area first for a short period, and then let the system water another spot in the yard while the slope absorbs the water it received. Then cycle back to apply more water to the slope. The same strategy can be used to water clay soils effectively.

Shady Lawns

Grass growing in the shade typically uses less water than grass in full sun. In general, you can water shady lawn areas less frequently than sunny ones. The exception, however, is grass growing under a tree. In these spots, the lawn is competing with tree roots for available moisture. You may need to actually water these areas more frequently than the ones that are shaded by your house or other objects.

Watering a New Sodded or Seeded Lawn

Newly sodded or seeded lawns need more irrigation than established turf. Typically, water new sod lawns heavily and daily for the first week. With sod, taper off watering after the first week to encourage grass to sink deep roots. Consult your local Sod supplier, or landscaping company for specific sod watering recommendations. For seeded lawns, twice daily watering is recommended. Aim to keep the top inch of soil consistently moist. Continue with daily irrigation until you have mowed the grass at least once. Oscillating sprinklers are a better choice for new lawns until the grass takes root. Check out my article on seeding for more tips.

Don’t Let Water Hit the House

Sprinklers often spray water against the side of a home. You may have noticed some homes that have greenish spots on the outside. This is a sign of water damage and it can easily and quickly cause serious damage. Over time this can cause damage to the siding, brick, paint, or stucco of a home. It can also damage outdoor structures like barbecues, decks, outdoor kitchens, pool houses and sheds.

Many sprinkler systems, especially those in flowerbeds next to a home, were fine when first installed. But, over time, the bushes grow and the sprinkler heads need to be adjusted so that water is not blown onto the house, nearby windows, or other objects.

Persistent water spraying on your house can lead to mold and mildew developing on the outside, and even within, your walls, particularly if the house wrap (the moisture barrier behind the exterior siding) is damaged or leaking. In those cases, it could lead to the insulation getting wet and wood rot or deterioration. Stains and musty odor are two common symptoms of this.

If you have sprinkler heads nearby your house, check the walls for damage. A good time to do this is when adjusting the sprinkler heads. Any damaged wall areas should be cleaned and/or repaired which will help prevent future intrusion. If the damage requires the removal of part of the siding, be sure to check that the moisture barrier behind the siding is not damaged, ripped or torn.

CONCLUSION

In conclusion, with some diligent observation and attention to best practices, you can keep your lawn happy, healthy, and green all season long. Remember, water your lawn deeply but infrequently, water in the morning if possible,  monitor rainfall and how your sprinklers are performing, and listen to your lawn.  Happy watering!

 

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